War changes everything. War is an apocalypse and a technological revolution and a life-changing adventure, all rolled into one. So it's not surprising that many of science fiction's most indelible stories are about warfare.

Here are the 12 most important science fiction war stories of all time.

We asked on our Facebook page what your favorite science fiction war stories were, and we received over 300 responses. (Including one from the Facebook page for the John Dies at the End movie, which made our day.) Here's what you guys voted for.

12. Firefly
Joss Whedon's beloved Space Western show received a ton of votes, and at first we were a bit dubious. After all, we only glimpse the Battle of Serenity in a few scenes in the pilot. Was this just more proof that Browncoats can stuff any ballot box? But then we realized that it actually fits: Firefly really is about how war changes people, forever. Mal's past as a soldier continues to define him, and the Battle of Serenity does more than just name Mal's ship, it shapes everything. So yeah, this is a great science fiction show about war.

11. Warhammer 40K
This table-top gaming series, which takes place 38-odd thousand years from now, features the entire galaxy at war. And several people gave shout-outs to some of the tie-in novels that have been published for this game, including the Gaunt's Ghosts series written by genre veteran Dan Abnett, about one very special regiment, which are "like a scifi Band of Brothers," as Steve puts it. And the Horus Heresy books, which tell about a galaxy-wide civil war that took place 10,000 years before the game begins. "Just about any Warhammer 40K book is a great war story," says Brian.

10. Star Trek: Deep Space 9
The Dominion War might be the most ambitious story arc that Star Trek ever pulled off, with the Dominion being introduced in the show's second season and the war raging for a few years and culminating in the series finale. Trek had always explored questions about the ethics and strategy of war, going back to the Original Series and episodes like "A Taste of Armageddon" and "Balance of Terror." But with DS9, war is at its ugliest, and its most urgent — especially when Benjamin Sisko crosses some huge moral lines to bring the Romulans into the war, or when Nog loses his leg in battle. This was a war that the Organians couldn't just wave their hands and put a stop to.

9. Old Man's War by John Scalzi
People praise this series for its "kick-ass battles" and "sheer enjoyment," and for being a terrific shout-out to Heinlein's great military sagas, especially Starship Troopers, about which more in a bit. In this gritty future-war story, people who turn 75 are offered a miraculous rejuvenation, restoring them to perfect youth and vigor — and the only catch is that they have to go fight in a war that will probably kill them as quickly as old age would have. The "resolution is kind of awesome," says Keegan.

8. Armor by John Steakley
In this military SF classic, a man named Felix is a grunt in the advance guard of the invasion of the inhospitable planet Banshee. He just wants to get through his latest horrible mission in one piece — but luckily, he's got two things on his side: the most awesome powered armor imaginable, which is the culmination of 10,000 years of armor-making brilliance. And a mysterious being called the Engine, which protects him for some reason. Over at SFF Audio, Jesse Willis writes, "Armor synthesizes the action of Heinlein's Troopers with the emotional impact of Haldeman's The Forever War – but still comes off as a completely unique story."

7. War of the Worlds
The original interplanetary war story is still one of the most important — it's hard to overstate the importance of the first images of aliens coming to our planet and kicking our asses. The visceral, intense imagery sticks in your mind even today, like the main character's flesh getting scalded by the boiling water when the aliens unleash their heat ray. It's one of the most effective depictions of assymetric warfare from the standpoint of the less-equipped side, and a foundational war story of the genre. Image by Robert Czarny.

6. Star Wars
As various people pointed out, it has "war" in the title, which is usually a dead giveaway. But also, the original trilogy is pretty much all about the battles between the Rebellion and the Empire, with the Empire trying to establish final technological superiority through its Death Star program. These movies gave us dogfights in space, all-out assaults on Rebel bases, and massive explosions. People also praise Timothy Zahn's Thrawn Trilogy. But also, a whole new generation has grown up immersed in Clone Wars, which is a running saga about the costs of war.

5. Dune by Frank Herbert
This is one of the great foundational texts of science fiction, exploring the rise of Paul Muad'dib and the struggle with the Harkonnens over control over Arrakis, the source of the most valuable substance in the universe: the spice melange. Over the course of the first novel, Paul becomes the ultimate warrior. As Priness Irulan writes:

He was warrior and mystic, ogre and saint, the fox and the innocent, chivalrous, ruthless, less than a god, more than a man. There is no measuring Muad'Dib's motives by ordinary standards. In the moment of his triumph, he saw the death prepared for him, yet he accepted the treachery. Can you say he did this out of a sense of justice? Whose justice, then? Remember, we speak now of the Muad'Dib who ordered battle drums made from his enemies' skins, the Muad'Dib who denied the conventions of his ducal past with a wave of the hand, saying merely: "I am the Kwisatz Haderach. That is reason enough."

4. Battlestar Galactica
The rebooted BSG took many of the themes from Deep Space Nine and pushed them much further. The show takes place years after the First Cylon War, in which unbelievable bloodshed and destruction came from a robot uprising. And now, the Cylons have returned and wiped out most of humanity, leaving the survivors facing the possibility of extinction. War creates refugees and includes genocide, and these are realities that BSG looks at with an unblinking eye. As several people said, the whole run of episodes from the first miniseries to the Battle of New Caprica is must-watch television.

3. Ender's Game by Orson Scott Card
Soon to be a movie, this novel contains a dark, insane metaphor for the ways in which war corrupts young people — Ender Wiggin is turned into a "Xenocide" without his knowledge, and his talent for slaughter becomes legendary across all human civilizations. (Click here for an MS-paint cartoon synopsis of the novel.) It's totally brutal, and early indications are that the forthcoming movie is going to include a lot of that same intensity and zero-gravity violence.

It looks like the Ender's Game movie is really moving forward, with Gavin Hood (Wolverine) as…
Read more Read more

2. The Forever War by Joe Haldeman
Even decades later, Haldeman's depiction of the realities of interstellar travel — and particularly, of the time dilation that traveling light years would cause — still seem groundbreaking and unique. The war against the Taurans goes on and on, and William Mandella is more and more a man out of time, facing a universe that no longer makes sense to him. This book pulls no punches in depicting the culture shock that a returning veteran faces, when everybody else has moved on in the meantime. By the time the war is over, Mandella has only aged a decade but it's been over a thousand years — and then we find out the war wasn't even really worth it. Ridley Scott was going to film this book at one point, and it would be great to see that happen instead of Prometheus 2.

1. Starship Troopers by Robert A. Heinlein
Skip the Verhoeven movie version, and go straight to the source material — the original novel about power-armored soldiers in space fighting insect aliens. Writes Gregory, "Apparently Starship Troopers the book is prescribed reading at the US Marines college. Heinlein's concepts of futuristic war and powered armour were visionary." Adds Marc, "if you think it's fascist, you missed the whole point of the book." This is being made into a whole new movie, and let's hope it's closer to the book this time.